1. Field of the Invention
The present invention relates to an ultra fine groove chip (or tip) having less susceptibility of the working surface to thermal damage during the working in shear (ductile) mode and having high efficiency in disposing of swarf, and to an ultra fine groove tool provided with the ultra fine groove chips.
2. Description of the Related Art
With such difficult-to-cut brittle hard materials such as metal, crystals, glass or the like, it is vitally important to maintain the sharpness of tips by maintaining working resistance at a low level and by controlling heat, thereby maintaining the quality of work surface constant.
Brittle hard materials are particularly susceptible to surface cracking during working, which often is a cause of brittle fracture. The susceptibility to cracking of the brittle hard material is more pronounced when a larger-edged tool is used in any grinding, cutting or lapping process. Further, the fracture of a material occurs more often in a "brittle mode", which shall be considered to mean, throughout this specification, a state, wherein the surface of the brittle hard material is covered with cracks, as is often seen in a case when glass is rubbed with rough sandpaper, white powder is generated, and the glass turns opaque due to cracks produced on its surface.
Generally, when grinding a brittle hard material, swarf generated by brittle-mode grinding tends to be rough, and those by shear-mode tend to be fine and uniformly shaped. Here, the "shear mode" (or ductile mode) shall be understood to mean, throughout this specification, the following state. For example, the glass, as described above, if rubbed with a rough sandpaper, generates white powder and turns opaque due to cracks on its surface. On the other hand, if rubbed with a fine sandpaper under a very slight pressure, no white powder is generated and no cracking is caused. Such a crack-free state of the glass surface is called the shear mode where the initial transparency of the glass is mostly maintained after the glass is ground with very fine sandpaper under very slight pressure.
As an example of a tool employed for such working processes for workpieces as grinding, lapping, polishing or cutting, diamond grinding wheels are known for their excellent characteristics in performance, durability, precise finishing and so on.